United Kingdom in the Napoleonic Wars

Between 1803 and 1815, Great Britain was the most constant of Napoleon's enemies. Through its command of the sea, subsidies to allies on the European mainland, and active military intervention in the Peninsular War, Britain played the central role in Napoleon's downfall even as all the other major powers switched back and forth.

In May 1803, war was declared again. Napoleon's plans to invade Britain failed due to the inferiority of his navy, and in 1805, Lord Nelson's fleet decisively defeated the French and Spanish at the Battle of Trafalgar, which was the last significant naval action of the Napoleonic Wars.

The series of naval and colonial conflicts, including a large number of minor naval actions, resembled those of the French Revolutionary Wars and the preceding centuries of European warfare. Conflicts in the Caribbean, and in particular the seizure of colonial bases and islands throughout the wars, could potentially have some effect upon the European conflict. The Napoleonic conflict had reached the point at which subsequent historians could talk of a "world war". Only the Seven Years' War offered a precedent for widespread conflict on such a scale.

Napoleon also attempted economic warfare against Britain, especially in the Berlin Decree of 1806. It forbade the import of British goods into European countries allied with or dependent upon France, and installed the Continental System in Europe. All connections were to be cut, even the mail. British merchants smuggled in many goods and the Continental System was not a powerful weapon of economic war. There was some damage to Britain, especially in 1808 and 1811, but its control of the oceans helped ameliorate the damage. Even more damage was done to the economies of France and its allies, which lost a useful trading partner. Angry governments gained an incentive to ignore the Continental System, which led to the weakening of Napoleon's coalition.

The British army remained a minimal threat to France; the British standing army of just 220,000 at the height of the Napoleonic Wars hardly compared to France's army of a million men—in addition to the armies of numerous allies and several hundred thousand national guardsmen that Napoleon could draft into the military if necessary. Although the Royal Navy effectively disrupted France's extra-continental trade—both by seizing and threatening French shipping and by seizing French colonial possessions—it could do nothing about France's trade with the major continental economies and posed little threat to French territory in Europe. In addition, France's population and agricultural capacity far outstripped that of Britain.

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Wikipedia